-Bottom is Arca Swiss dovetail, Compatible with tripod ball head of ARCA-SWISS and RRS. -Lens collar is made of aviation aluminum, CNC precision machined, hollow weight reduction design, surface polished and anodized, with stainless steel screws; -Adopt original factory standard, with 3M film inside, inner diameter is about 81.5mm, width is about 18mm; The bottom is added a quick release plate feature, the length of the plate is about 90mm, with 1/4 and 3/8 screw holes and stainless steel anti-slip screw, the net weight is about 180g; -The lower quick release plate is Swiss arca standard, compatible with RRS / ARCA-SWISS / PMG / WIMBERLEY / MARKINS / SUNWAYFOTO / BENRO / SIRUI / MARSACE / ISHOOT Package -1 x quick release ring iShoot IS-TA140 Tripod Mount for Tamron 100-400mm f/4.5-6.3 Di VC USD Lens(A035) (Other items in photos not listed here are for illustration only, not included) Note: A. Import duties, taxes and charges are not included in the item price or shipping charges. These charges are the buyer's responsibility. B. Please check with your country's customs office to determine what these additional costs will be prior to bidding/buying.